Safety device for wells



INVENTOR Afro/Mfrs J. E. MICDOWELL. SAFETY DEVICE Foa wELLs. I

APPLICATION FILED APR. 26| 1920. v 1,370,140, Patented Mar. 1,1921.

J 77M Don/Eab,

WITNESSES JOHN FRANK MCDOWELL, 0E snREvEPonr, LOUISIANA.' A

snrE'rY' DEVICE 'Eon WELLS.

Specification of Letters Patent.

Application filed April 26, 1920. Serial No. 376,698. i Y

To @ZZ/whom t may concern:

Be it known that I, JOHN FRANK Mo- DOWELL, a citizen of the United States, and a resident of Shreveport, in the parish of Caddo and State of Louisiana, have invented certain new and useful Improvements in Safety Devices for Wells, of which the following is a specification.

My invention is an improvement in safety devices for wells, and has for its object to provide a device of the character specified which may be arranged at the top of the well casing, about the drill stem or other tools, for preventing downward movement of the said tools or drill stem during the raising thereof, the said means being inthe form of a collar through which the stem passes and having means for gripping the stem when it moves downwardly and for releasing the stem when it moves upwardly.

In the drawings:

Figure 1 is a sectional view of a portion of a well casing, with the safety device in place;

Fig. 2 is a top plan View of the device;

Fig. 3 is a vertical section.

The present embodiment ofthe invention is shown in connection with a drill stem l arranged in the well casing 2, and the improvement comprises a sleeve or collar 3 of suitable thickness and of a diameter such of the said recesses opening into the bore ofv the collar, as clearly shown in Fig. 3. s

The opening 5 at the lower end of each recess will be substantially triangular, as

shown in Fig. 3, the largest end of the opening being downward, and because of the inclined arrangement of the recesses 4 the depth of the opening 5 will decrease toward the wide ends of the said openings, that is, j

the openings 5 will be shallower at their lower ends than at their tops.

A ball 6 is arranged in the recess 4, each of the balls being of a diameter such that it will fit smoothly in the recess and will move *marianna-e1, 1921....,

freely therein. The openings 5 are ofa size i such that the balls will not pass through the said openings, while at the same time they are of sufficient size to permita considerable portion of the ball to extend into the bore of the collar.

The upper ends of the re'-v cesses 4 are closed vin any suitable manner,

as, for instance, by plugs indicated' at 7, and

these plugs maybe held in the recesses'inl drill stem or tools passing through the col` lar. In practice,V some means will be provided. for simultaneously raising the balls, so that they may be held out of engaging posltion during the operationr of the drill. It will be obvious that when the balls are not held out of engaging position, that is, when they r est in the bottoms of the recesses 4, they will grip the stem l and will prevent downward movement thereof. The weight of the stem tends 'to tighten the balls and to tighten the collar on the stem. When the stem is moved upwardly the balls are released and permit the free upward movement of the stem. Referring to Fig. 3, it will be seen that the recesses 4 open at different levels in the collar. Some of these recesses open near the lower end and others near the top, whileV others open at various distances intermediate the ends. l

I claim: f Y

1. A device of the character specified comprising a collar of an internal diameter to receive a drill stem and of an external diameter to prevent movement into the well and opening at their lower ends into thel boreofy the collar, balls in the recesses, the

kopenings into the bore of the collar being of a size to prevent the complete passage of the balls butto permit a considerable portion ofthe ball to extend into the bore ofthe collar.

2. A device of the character specified,

casing, said collar having means for gripiodo ameter to prevent movement of the collar.

into a Well easing, lthe collar having openings extending longitudinally thereof, from *I its upper edge inclining inwardly to open into the lumen intermediate the ends thereof, said openings into the lumen of the collar being at various depths, and bolts n the opening of a size to prevent their passage 10 through the'openings but to cause them to extend-into the lumen of the collar.

JOHN FRANK MCDOWELL. 

